Rapid aromatization of Hantzsch-1,4-DHPswith t-butylhydroperoxide catalysed by iron(III) phthalocyanine chloride is described. The reaction proceeds smoothly at room temperature within 1-35 min and the products of high purity were isolated in excellent yields. To explain the reactivity of this catalytical system plausible mechanism have been proposed to involve formation of high-valent oxoferryl species as in cytochrome P450 itself. (C) 2008 Elsevier Ltd. All rights reserved.
Oxidative aromatization of 1,4-dihydropyridines and pyrazolines using HbA–H2O2: An efficient biomimetic catalyst system providing metabolites of drug candidates
作者:Atul Kumar、Ram Awatar Maurya、Siddharth Sharma
DOI:10.1016/j.bmcl.2009.05.056
日期:2009.8
Human hemoglobin (HbA) efficiently catalyses the oxidative aromatization of 1,4-dihydropyridines (1,4-DHPs) and pyrazolines with hydrogen peroxide in phosphate buffer. The results of the study reveal that the rates of oxidative aromatization of 1,4-DHPs are substituent dependent. Thus, the present study is very useful in understanding the metabolism of 1,4-DHP drugs in liver by cytochrome P450 and designing novel drugs as well as modifying the existing drugs for better pharmacokinetic profile. (C) 2009 Elsevier Ltd. All rights reserved.
An efficient, metal-free, room temperature aromatization of Hantzsch-1,4-dihydropyridines with urea–hydrogen peroxide adduct, catalyzed by molecular iodine
A mild, highly efficient and metal-free synthetic method for aromatization of 1,4-dihydropyridines employing urea–hydrogen peroxide adduct as oxidant catalyzed by 20 mol % of molecular iodine was developed. The reaction was carried out in ethyl acetate at roomtemperature and the products were isolated in high to excellent yields. A plausible free-radical mechanism is proposed based on results obtained